ON IMPACT WITH A LIQUID SURF.M 189 



side and a " sound of splash " was recorded. On the left side there is no dis- 

 turbance of the "smooth splash " ; on the right is a " pocket" of air such as was 

 obtained by accident in Series VI., fig. 4, of the earlier paper (here reproduced as 

 fig. 2A for convenience of reference and to help the reader to interpret correctly the 

 first and second figures of the present series). The point of departure at which the 

 liquid left the sphere is well marked, and a tangent from this point passes through 

 the outermost conspicuous droplets that must have been projected from it. 



In fig. 2 the sphere was dusted at the top and on the right-liand side, but not much 

 more than halfway down, and the configuration corresponds entirely to the facts. 

 Here again a tangent from the well marked drops on the right-hand side leads very 

 nearly to the place of departure from the surface of the sphere. 



In fig. 3 on this page the record is that the sphere was dusty at the top only. It 

 is to be expected that dusting at the top will not make much diflference in the flow of 

 the already converging liquid. Comparison with fig. 7 of Series XIII., Plate 3 shows, 

 however, that a slight effect has been produced. 



Series XX. 



Fig. 3. 



Fig. 4. 



In fig. 4 the sphere was dusted at the bottom only. The appearance on the left- 

 hand side seems to show that the liquid has, after leaving the sphere, again been 

 brought within reach. This recovery at an early stage is explained by reference to 

 photographs of Series X. of the splash of a rough sphere, which show that even the 

 rough sphere is soon wetted for some distance up the sides, as we may imagine by the 

 gradual passage of the sphere into the divergently flowing cone of liquid which 

 surrounds the lower part. When the liquid again touches a polished part the film 

 will be again guided up it in the manner already explained. In figs. 5 and 6 (shown 

 in drawings on page 190) the sphere was out of focus through the slipping out of 

 place of the rod which held the releasing gear a fault which was not discovered till 



